1. Field of the Invention
The present invention relates to a laminated ceramic electronic component.
2. Description of the Related Art
Electronic devices with laminated ceramic electronic components such as a laminated ceramic capacitor and a laminated ceramic substrate are becoming smaller in size with an attempt to achieve higher performance and greater functionality. In order to keep up with the technology trends, it is also required to improve characteristics and achieve downsizing of the laminated ceramic electronic components by further thinning, multi-layering, and greater density.
The laminated ceramic electronic components generally include a functional layer embedded with an internal electrode and protective layers disposed on both sides of the functional layer. Typically, since no internal electrode is embedded in the protective layer, the protective layer differs from the functional layer in burning shrinkage and thermal expansion coefficient. For instance, it is often the case that the protective layer of the laminated ceramic capacitor has a higher burning shrinkage and a lower thermal expansion coefficient than the functional layer.
The difference in burning shrinkage/thermal expansion coefficient between the functional layer and the protective layer produces a large stress along an interface between them during the process of manufacturing the laminate ceramic electronic components, which tends to cause separation, delamination and cracks. Particularly, there is a problem that cracks tend to be caused by heat treatment (or annealing) or burning with stress remaining therein.
Japanese Patent Application Publication No. 2003-309039 discloses a technology of preventing delamination and cracks by adjusting the binder content of the protective layer and the difference in burning shrinkage between the functional layer and the protective layer.
However, the technology disclosed in JP 2003-309039 has a problem of complicating the manufacturing process because of the necessity of a plurality of sheets with different binder contents.
In addition, since the stress and physical strain along the interface between the functional layer and the protective layer increase with thinning and multi-layering, the above-mentioned problems are becoming more prominent due to thinning, multi-layering, and greater density of recent laminated ceramic electronic components.